sys/src/cmd/tapefs/tapfs.c

   1 #include <u.h>
   2 #include <libc.h>
   3 #include "tapefs.h"
   4
   5 /*
   6  * File system for old tap tapes.
   7  */
   8
   9 struct tap {
  10         unsigned char   name[32];
  11         unsigned char   mode[1];
  12         unsigned char   uid[1];
  13         unsigned char   size[2];
  14         unsigned char   tmod[4];
  15         unsigned char   taddress[2];
  16         unsigned char   unused[20];
  17         unsigned char   checksum[2];
  18 } dir[192];
  19
  20 int     tapefile;
  21 char    buffer[8192];
  22 long    cvtime(unsigned char *);
  23 extern  int verbose;
  24 extern  int newtap;
  25
  26 void
  27 populate(char *name)
  28 {
  29         int i, isabs;
  30         struct tap *tpp;
  31         Fileinf f;
  32
  33         replete = 1;
  34         tapefile = open(name, OREAD);
  35         if (tapefile<0)
  36                 error("Can't open argument file");
  37         read(tapefile, dir, sizeof dir);
  38         for (i=0, tpp=&dir[8]; i<192; i++, tpp++) {
  39                 unsigned char *sp = (unsigned char *)tpp;
  40                 int j, cksum = 0;
  41                 for (j=0; j<32; j++, sp+=2)
  42                         cksum += sp[0] + (sp[1]<<8);
  43                 cksum &= 0xFFFF;
  44                 if (cksum!=0) {
  45                         print("cksum failure\n");
  46                         continue;
  47                 }
  48                 if (tpp->name[0]=='\0')
  49                         continue;
  50                 f.addr = tpp->taddress[0] + (tpp->taddress[1]<<8);
  51                 if (f.addr==0)
  52                         continue;
  53                 f.size = tpp->size[0] + (tpp->size[1]<<8);
  54                 f.mdate = cvtime(tpp->tmod);
  55                 f.mode = tpp->mode[0]&0777;
  56                 f.uid = tpp->uid[0]&0377;
  57                 isabs = tpp->name[0]=='/';
  58                 f.name = (char *)tpp->name+isabs;
  59                 if (verbose)
  60                         print("%s mode %o uid %d, %s", f.name, f.mode, f.uid, ctime(f.mdate));
  61                 poppath(f, 1);
  62         }
  63 }
  64
  65 long
  66 cvtime(unsigned char *tp)
  67 {
  68         unsigned long t = (tp[1]<<24)+(tp[0]<<16)+(tp[3]<<8)+(tp[2]<<0);
  69         if (!newtap) {
  70                 t /= 60;
  71                 t += 3*365*24*3600;
  72         }
  73         return t;
  74 }
  75
  76 void
  77 popdir(Ram *r)
  78 {
  79         USED(r);
  80 }
  81
  82 void
  83 dotrunc(Ram *r)
  84 {
  85         USED(r);
  86 }
  87
  88 void
  89 docreate(Ram *r)
  90 {
  91         USED(r);
  92 }
  93
  94 char *
  95 doread(Ram *r, vlong off, long cnt)
  96 {
  97         if (cnt>sizeof(buffer))
  98                 print("count too big\n");
  99         seek(tapefile, 512*r->addr+off, 0);
 100         read(tapefile, buffer, cnt);
 101         return buffer;
 102 }
 103
 104 void
 105 dowrite(Ram *r, char *buf, long off, long cnt)
 106 {
 107         USED(r); USED(buf); USED(off); USED(cnt);
 108 }
 109
 110 int
 111 dopermw(Ram *r)
 112 {
 113         USED(r);
 114         return 0;
 115 }